1. Field of the Invention
This invention relates to containers having a coating layer on the surface of a papery base structure, suitable for use as tablewares or for decorative purposes, and to a method for producing same.
2. Description of the Prior Art
Containers for use as tablewares or for decoration are made of variety of materials including, in addition to wood, metals such as copper, iron and aluminum and other inorganic materials such as glass and ceramic materials. Wooden containers are largely classified into plain wooden containers exposing unvarnished wood surfaces and coated wooden containers having the wood surfaces covered with a coating.
Because of the features such as lightness and excellent heat retention by heat insulation, wooden containers are extremely useful as tablewares for soup or other watery dishes. Especially lacquer wares with a coating of Japanese lacquer on a shaped wooden base structure have not only a good moisture-proofing property but also excellent decorative effects, in addition to excellent properties in resistance to chemicals, weather durability, heat resistance and sturdiness, so that they are considered valuable not only as articles for practical use but also as decorative articles.
The lacquer wares are generally made by coating a shaped plain wooden structure with a lacquer consisting of Rhus Trichocarpa Mig., Rhus Ambigausa L., Rhus Succedeanea L or the like which is obtained by processing and refining the sap tapped from trees of Rhus genus. The lacquer is coated as it is or after admixing thereto a pigment for coloration, forming a coating of a single layer or plural number of layers on the wooden base structure.
In a case where shaped wood structure is used as a base for a container as described hereinbefore, it is necessary to dry the wood for a long time period after lumbering since cracks easily occur in a coating on insufficiently dried wood during use. Besides, the machining operation for cutting wood into a particular shape depending upon the purpose of use requires a meticulous skill, and the usable part of the lumber is as small as 10%, resulting in a low yield which is reflected by drawbacks such as high cost and infeasibility of mass production in addition to fragility in directions parallel with the wood grains.
Therefore, in order to produce at low cost containers with a coating of high decorative nature like a lacquer coating, it is known to employ a synthetic resin for the container base structure, which is formed into a desired shape by injection molding or the like. However, containers which have a synthetic resin base are inferior in the heat insulating property, with possibilities of softening when hot soup or the like is put in the container. Further, it is necessary to employ expensive molds for shaping the synthetic resin material, which molds are suitable for mass production but not for small-scale production of containers of different types.